Impedance‐tube calibration of a reverberant room for the measurement of sound power in tones

1976 ◽  
Vol 59 (6) ◽  
pp. 1393-1398 ◽  
Author(s):  
David Alan Bies ◽  
Colin H. Hansen
Keyword(s):  
Sound Power ◽  
Impedance Tube

Use of an impedance tube as a standard sound‐power source

1976 ◽  
Vol 60 (S1) ◽  
pp. S100-S100
Author(s):  
T. M. Proctor ◽  
R. K. Cook
Keyword(s):  
Power Source ◽  
Sound Power ◽  
Impedance Tube

Active control of compressor noise in the machinery room of refrigerators

2019 ◽  
Vol 67 (5) ◽  
pp. 350-362
Author(s):  
J. M. Ku ◽  
W. B. Jeong ◽  
C. Hong
Keyword(s):  
Control System ◽  
Active Control ◽  
Weighting Function ◽  
Reference Signal ◽  
Active Noise Control ◽  
Dominant Frequency ◽  
Time Signal ◽  
Frequency Noise ◽  
Sound Power ◽  
Fxlms Algorithm

The low-frequency noise generated by the vibration of the compressor in the machinery room of refrigerators is considered as annoying sound. Active noise control is used to reduce this noise without any change in the design of the compressor in the machinery room. In configuring the control system, various signals are measured and analyzed to select the reference signal that best represents the compressor noise. As the space inside the machinery room is small, the size of a speaker is limited, and the magnitude of the controller transfer function is designed to be small at low frequencies, the controller uses FIR filter structure converged by the FxLMS algorithm using the pre-measured time signal. To manage the convergence speed for each frequency, the frequency-weighting function is applied to FxLMS algorithm. A series of measurements are performed to design the controller and to evaluate the control performance. After the control, the sound power transmitted by the refrigerator is reduced by 9 dB at the first dominant frequency (408 Hz in this case) and 3 dB at the second dominant frequency (459 Hz here), and the overall sound power decreases by 2.6 dB. Through this study, an active control system for the noise generated by refrigerator compressors is established.

Sign in / Sign up

Export Citation Format

Share Document